Viagra (Sildenafil Citrate) – Comprehensive Patient Information for Australia
Basic Product Information
| International Nonproprietary Name (INN) | Sildenafil Citrate |
| Common Brand Names in Australia | Viagra, Vedafil, Kamagra, Silvasta |
| ATC Code | G04BE03 |
| Available Forms & Strengths | Film-coated tablets (25 mg, 50 mg, 100 mg) |
| Manufacturers | Pfizer Australia Pty Limited; various generic manufacturers |
| Prescription Status (Australia) | Prescription Only (Schedule 4 medication) |
Mechanism of Action
For Patients: Sildenafil citrate works by improving blood flow to the penis, making it easier to get and keep an erection when you are sexually aroused. It does this by relaxing the blood vessels in the penis, allowing more blood to flow in.
For Healthcare Professionals: Viagra is a selective phosphodiesterase type 5 (PDE5) inhibitor. It enhances the effect of nitric oxide (NO) by inhibiting PDE5, which increases cyclic guanosine monophosphate (cGMP) levels. This leads to smooth muscle relaxation in the corpus cavernosum and promotes penile erection in response to sexual stimulation.
Pharmacokinetics
- Absorption: Rapidly absorbed after oral administration. Maximum blood levels typically reached within 30–120 minutes (median ~60 minutes).
- Metabolism: Mainly by hepatic CYP3A4 (major route) and CYP2C9 isoenzymes.
- Elimination: Primarily excreted as metabolites in faeces (80%) and urine (13%).
- Duration of Action: Effects generally last for 4–6 hours. Some effect may persist up to 8 hours in some individuals.
Use in Everyday Life & Best Practices
- Typical Doses: The recommended starting dose is 50 mg taken as needed, about one hour before sexual activity. Based on effectiveness and tolerability, the dose can be increased to 100 mg or decreased to 25 mg.
- How to Use: Swallow one tablet whole with water, usually about 30–60 minutes before planned sexual activity. Do not take more than one dose per day.
- English Context: In Australia, Viagra should only be used as prescribed by your GP or urologist and picked up from a registered pharmacy. Online prescriptions are also valid if issued by an AHPRA-registered prescriber.
Dosing in the Morning vs Evening
- Morning Use: May be suitable for those whose sexual activity occurs earlier in the day, but may be less convenient due to daily routines or work commitments.
- Evening Use: Most Australian patients prefer evening dosing, aligning with typical sexual activity patterns. However, avoid taking immediately after large or fatty meals, as this may delay the effect.
- Tips: Take Viagra at a similar time if used regularly to establish a predictable effect. Always allow at least 24 hours between doses.
Taking with Food or on an Empty Stomach
- Effect of Meals: Taking Viagra on an empty stomach allows for the quickest absorption. If taken with food, particularly high-fat meals common in the English-Australian diet (e.g., steak, full English breakfast), onset may be delayed by 30–60 minutes.
- Recommendation: Swallow with water on an empty stomach or after a light meal for best results.
Interaction Warnings
| Substance/Food | Interaction | Clinical Advice |
| Alcohol | May increase risk of side effects (dizziness, hypotension); may reduce effectiveness | Limit or avoid alcohol when using Viagra |
| Nitrates (e.g., GTN for angina) | Severe drop in blood pressure, risk of cardiovascular events | Contraindicated; do not use with any nitrate medicines |
| Alpha-blockers (for prostate or blood pressure) | Can cause symptomatic hypotension | Stabilise on alpha-blocker first, start with lowest Viagra dose |
| Ritonavir & other strong CYP3A4 inhibitors | Increases sildenafil blood levels, increases risk of side effects | Lower maximum dose, caution advised |
| Grapefruit juice | May delay metabolism, increases blood levels | Avoid consuming grapefruit or juice |
| Other ED drugs (tadalafil, vardenafil, etc.) | Increased risk of side effects and complications | Do not combine with other ED medicines |
Indications
| Indication | Status | Supporting Evidence |
| Erectile dysfunction (ED) in adult men | Approved/Official | TGA, PBS, clinical guidelines |
| Pulmonary arterial hypertension | Approved (as Revatio, separate product/dosing) | TGA, specialist prescription |
| Raynaud’s phenomenon, altitude sickness, female sexual arousal disorder | Off-label | Specialist/small studies; not TGA-approved for these uses |
Dosing According to Clinical Indication
| Population | Indication | Usual Dose | Max Frequency | Notes |
| Adults | Erectile Dysfunction | 50 mg as needed, 30–60 min prior | Once per 24 hours | Adjust to 25–100 mg based on effect |
| Elderly (>65 yrs) | Erectile Dysfunction | Start at lower end (25 mg) | Once per 24 hours | Monitor for adverse effects |
| Pulmonary Hypertension (adults) | PAH (as Revatio) | 20 mg 3 times daily | - | Specialist only – do not substitute for Viagra |
| Children | Not approved for ED | NA | NA | Do not use |
Safety Profile and Side Effects
- Very Common:
- Headache, flushing, nasal congestion, dizziness
- Common:
- Indigestion, visual disturbances (blue tinge, blurred vision), muscle pain
- Uncommon – Rare:
- Rash, nosebleed, sudden hearing loss, prolonged/painful erection (priapism), heart palpitations, severe allergic reaction (anaphylaxis)
- Warnings:
- Seek immediate medical help for chest pain, severe dizziness, loss of vision, or erections lasting more than 4 hours
- Do not use if you have had recent stroke, severe heart/kidney/liver disease, or are on nitrate therapy
Guidelines for Proper Use – Advice from Your Pharmacy Team
- Always use as prescribed, never share Viagra with others.
- Take the lowest effective dose to reduce side effects.
- Do not exceed one dose per 24 hours.
- Avoid large, fatty meals around the time of dosing.
- Limit alcohol intake to reduce risk of dizziness or low blood pressure.
- Store tablets in a cool, dry place under 25°C, out of sight and reach of children.
- Consult your GP or pharmacist before starting or stopping any other medicines.
- Dispose of unused medication via a pharmacy return program.
Alternative Treatment Options
- Tadalafil (Cialis): Longer duration (24–36 hours), can be taken daily or as needed. Pros: Flexible timing, spontaneous activity. Cons: Higher cost, side effects may last longer.
- Vardenafil (Levitra): Similar onset to sildenafil, shorter duration. Pros: Effect if other PDE5 inhibitors ineffective. Cons: Similar side effects, food may affect absorption.
- Avanafil (Spedra): Faster onset, may be taken 15–30 minutes prior. Pros: Rapid action. Cons: Cost, availability.
- Non-oral options: Alprostadil (injectable or urethral), vacuum erection devices, psychosexual therapy. Note: PBS (Pharmaceutical Benefits Scheme) reimbursement for most oral PDE5 inhibitors is limited to specific medical conditions in Australia.
Legal, Registration, and Reimbursement Status in Australia
- Viagra (and generic sildenafil) is registered with the Therapeutic Goods Administration (TGA).
- It is a Schedule 4 (S4) medication—available only with a valid prescription.
- Pharmaceutical Benefits Scheme (PBS) reimbursement is restricted and usually limited to certain clinical indications (e.g., erectile dysfunction secondary to organic disease, pulmonary arterial hypertension as Revatio).
- No over-the-counter or pharmacy-only legal options for sildenafil in Australia.
Latest Research and Clinical Guidance (2022–2025)
- Contemporary Australian guidelines (Australian Therapeutic Guidelines: Sexual & Reproductive Health, 2023) reinforce sildenafil as first-line therapy for ED, with patient and partner preference and comorbid safety profiling as key factors.
- Meta-analyses and reviews (Lancet, 2022; BJU International, 2024) confirm sustained safety and efficacy of sildenafil in diverse populations, including elderly men and men with controlled cardiovascular disease (use under specialist advice).
- Ongoing studies explore benefit in selected female sexual disorders (off-label); no current TGA approval for these uses.
- Newer real-world data indicates high satisfaction, convenience, and overall improved quality of life for appropriate patients with prescription and pharmacist support (BMJ Open, 2023).
Availability and Delivery
| Pack Size | Typical Price Range (AUD) | Availability | Estimated Delivery (Major Cities) |
| 4 tablets (50 mg or 100 mg) | $25–$49 | In stock at most community & online pharmacies | Sydney: 24–48h; Melbourne: 24–48h; Brisbane: 1–2 days; Perth/Adelaide: 2–4 days |
| 8 tablets | $45–$80 | Most pharmacies | As above |
| 12–28 tablets (generic) | $60–$160 | Major pharmacies, online | As above |
Frequently Asked Questions (FAQ)
- Q1: How quickly does Viagra work and how long does it last?
A: Most men notice effects in 30–60 minutes. Erection-supporting effects may last four to six hours. Sexual stimulation is required for it to work. - Q2: Can I drink alcohol while taking Viagra?
A: Drinking small amounts (one or two standard drinks) is generally safe for most healthy men, but alcohol can reduce the effect and increase risk of low blood pressure and side effects. - Q3: Are there risks for people with heart conditions?
A: Yes – men with severe cardiac disease or angina (especially those taking nitrates) should NOT use Viagra. Always discuss with your GP if you have heart problems. - Q4: Is Viagra safe for older men?
A: Yes, but it should be started at the lowest dose and monitored for side effects, particularly dizziness and blood pressure drops. Always check with your healthcare provider. - Q5: Can I get Viagra over-the-counter in Australia?
A: No, it is a prescription-only medicine. You must consult a registered prescriber who will provide a valid prescription for dispensing at a licensed pharmacy.
For further advice, please speak to your GP, urologist, or community pharmacist. This information is designed to help support informed, safe, and confident use of Viagra as prescribed in Australia.
